Flow control with float type nonlinear resistance



March 22, 1960 v. STREETER 2,929,403

FLow CONTROL WITH FLOAT TYPE NONLINEAR RESISTANCE Filed Oct. l5, 1956siderable utility over varying ranges of use, trol of the ow of waterfor household use, for auto- .tive of pressure drop across the valve.desirable to provide a valve structurewhich is accurate United StateFLOW CONTROL WITH FLOAT TYPE NONLINEAR RESISTANCE Victor L. Streeter,Ann Arbor, Mich., assignor to The Dole Valve Company, Chicago, Ill., acorporation of Illinois Application October 15, 1956, Serial No.,615,785

Claims. (Cl. 137-517) 'The present invention relates to improvements inad'- fjustable tiow controls, and more particularly relates to a :iiowcontrol arrangement wherein a control valve is proyvided having amovable element with a non-linear posi-k ztional backing supplied by ashaped float.

motive use, for industrial uses andvarious other applications, it isdesirable to have a valve structure which is tent ice reliable and whichwill yield a constant flow rate irrespec- Further, it is ;and which isreliable and will not lose adjustment with 115B.

It is, therefore, an object of the vinvention to provide :an improvedtiow control valve whichwill obtain uni- ;form fiow with iiuctuations inpressure. i i

Another object is to provide an improved how control fdevice which willyield a constant ow with pressure :fiuctuations and which hasinstantaneous response and enhanced accuracy and reliability.

Another object of the invention is to provide a ow control having amovable valve member with an improved biasing means for supporting thevalve member and controlling its position relative to an orifice.

A still further object of the invention is to provide a non-linearsupport for a movable valve member used in a tiow control wherein thenon-linear support is provided by a fioat.

A still further object of the invention is to provide a oat supportedmovable valve member operative asa flow control wherein the dischargesetting can be easily adjusted.

A still further object of the invention is to provide a ow controlhaving an orifice with a relatively movable valve member therein tocontrol the cross-sectional ow area and having a oating backing memberfor the movable valve member which is designed to function in accordancewith the non-linear resistance law Another object of the invention is toprovide a tiow control having an orifice and a relatively movable valvemember therein to adjustably control the cross-sectional ow openingwherein the movable member is connected to a float which is designed inaccordance with the relationships 2,929,403 Patented Mar. 22, 1 960whereby a non-linear resistance is provided for the movable valve memberto obtain constant iiow with varying head. e

= Another object of this invention is to provide a shaped float.providing a non-linear resistance for controlling a movable member of afiow control valve having a profiled throat formed in accordance withthe relationship i --i-tl-tfl-wfri Other o bjects, features andadvantages of the present invention will become more apparent with thecomplete disclosure of the invention in the following detaileddescription of the specification, claims and accompanying drawingsinwhich:

Figure l is a partially diagrammatic presentation of a structureembodying the principles of the present invention; and j j Figure 2 is aschematic presentation of the non-linear float resistance with thedimensions indicated from which the designrrelationships are developedand disclosed.

As illustrated in the drawings and as will be described in detail, thedisclosed preferred embodiment presents a ow control wherein an oricemember is provided having a surface of revolution to coact with amovable .poppet diskto regulate the cross-sectional liow area throughthe orifice with changes in head of the fluid fiow therethrough. Thepoppet is given a non-linear backing orsupport to control its positionprovided by a oat housed in achamber and resting in a fluid. The-fioatis provided with a profile to provide the proper non-linear forcedisplacement relationship.

As illustrated in Figure 1the fiow control has a housing 4 provided withan inlet 6 and an outlet 8, with the ow of uid to be controlled enteringat the inlet and beingdischarged at the outlet. Between the inlet andoutlet is an orifice defining member 10 providing a central orice orthroat 12 therethrough. The orifice member has a specially shapedprofiled face 14 to provide a throat between it and the movable poppetdisk or head 16.

The disk is so designed as tol have a knife-edge 18 which will provide aow of suitable characteristics between it and the face 14 of the orificewithout unnecessary ow loss factors.

The poppet disk 16 is supported on a stem 19 which is secured in anadjustable connector member 20. The connector member is in the form of asleeve having a cylindrical opening 22 therethrough with the poppet stemprojecting into the upper end of the cylindrical opening and asupporting rod 24 projecting into the lower end of the connectingmember. The stem is held in place within the sleeve by a set screw 26threaded radially into the sleeve to bear against the stem and secure itin its position within the sleeve. The rod 24 is also secured within thesleeve by a set screw 28 threaded radially into the sleeve and securingthe post therein. It will be apparent that the position of the diskrelative to the supporting rod and hence the float 34 may be readilyadjustable in a vertical direction by loosening either of the set screwsand moving the disk up or down relative to sition.

K as being of mercury, although other forms of fluid may be utilized. AtVthe top of the chamber is a plate 35 preventing direct contactengagement of the top of the float 34 by the tiuid passing through thevalve. A hole 37 is provided4 in the plate so that the rod 24, can movefreely therethrough and so that'the pressuren on each side of the platewill'be substantially the same.

The orifice and poppet combination is similar to thatA disclosed in mycopending patent application Adjustable Flow Control, Serial No`446,867, filed July 30, 1954. The envelope or profile of the orifice isdesigned to avail movement of the poppet in accordance with thequadratic relationship between the flow and the head. The surface ofrevolution or the envelope of the orifice is constructed to follow thelaw C.,A=(o,.4 min e 2179 (1) It is to be understood that although theorifice member is profiled and the poppetv is thin edged, theconstruction could for certain purposes be altered with a thin orificemember and profiled poppet. Also the orifice could be constructed as themovable member with the poppet fixed in position. Y

The throat of the envelope is constructed in accordance with therelationship Serum/1 Inl-Ih For this poppet and orifice throatrelationship, a non linear support is provided for the movable` valvemember, shown as the poppet in this case. A float support is utilizedfor the movable valve member to obtain the non-` linear resistancenecessary. The displacement of the heavy liquid by a profiled float,moving vertically within thel float chamber, provides the means ofobtaining a force displacement that is exponential. The pressureY dropacross the poppet disk forces the fioat into the mercuryI causing it torise along the sides of the lioat, thereby iiibe varied. The presence ofwater or other liquid fiow-Y ing above the oat and in contact with themercury or other heavy liquid is taken into account by the'calculationsshown below. The weight of poppet disk, rod and oat can be balanced bybuoyant force of the owing liquid on the oat or by an extension` of thebottom of the oat into the heavy liquid. `It will Vbe understood,however, that the valve could be designed in accordance with theprinciples `of my invention so as to have a fixed poppet and movableorifice 'in which case the profile of the orifice would have to beinverted. lt will also be understood that a knife-edge orifice could 'beYadopted with a profiled poppet. For convenience the disc or pop-A petwill be described herein 'as movable and the orificev ments.

In some instances it may be desirable to provide a yflow meter. With theapplication of the principles of the present invention the structure canbe modified to obtain a ow meter. The orifice member 10 is reversed inits position so that it has an increasing cross-sectional area inadownstream direction. The. non-linear float backing for the poppetmember will then permit it to move as a 'ow meter. The ow will belinearly proportional to the pressure drop across the poppet and byutilizing a device responsive to pressure differential, such as amanometer, and connecting it upstream and downstream of the valve, theflow can be read from a linear y scale.

To calculate the cross-sectional area ofthe float in terms of elevationz' above its bottom, reference is made to Figure 2 of the drawings. lawvin accordance with which the oat backing performs is a ln H F=F0 Y (a)where s varies from zero to Y0 and F from- F0 to FOH.

" For a displacement, 5s of the tioat, a volurneas of liquid 6F=i z+saav t4) Using the continuity equation i ask-(ao-al (5) the buoyant forcechange becomes a Y: l aan aF as(ao a+1)aa-, asaraay (6) differentiatingEq.3 l*

' ln II 5F-F01; He s (7) 0 and equating values of 6F in (6) and (7) ilnH Vm11,' FlnH "y Y i Illu-GAY- Yo e n (8) Solving for i a a: c sin H-(9) 1+ aY/v eff-.1T Fg v Equation 9 yields the cross-Sectional area ofthe iioat in terms of s. It must now be related to z'. For displacementsY Y z'=s+5t (l0) and," from Eq. 5

sao z -a -D a (11) Eliminating a in Eq. 6, 7 and ll s 1n II F0111 H r lY dz (vl-l-aYoAve da (l2)` Integrating -Lll l= 0 Yo i t t z s|A0A Ye j-icons an Let z =0'when s='0, then ,F ,.Iln H I= u- Y e l s-l-aor1r e. 1(13) Equations 9 and 13 permit o and z' to be computed-Vin;

terms of the parameter s.

As an example of a float which may be used in accordance with theprinciples of the invention, the following The non-linear resistanceexample is given. This example has not been corrected for capillarity.

Y Example a: 0.2906 a:monache-9212' 'Ihe following chart indicatesvarious related values 25' for the float:

.l In the mathematical definition for the structure, symbols used havethe following general meaning:

A=area of opening between disk and throat Cddischarge coefficient 40e=base of natural logarithme F=pressure of force on. disk F0=minimumdesign force ondisk H=ratio of maximum fluid head to minimum uid headh=head drop across disk h0=n1inimum design head loss across diskln==natural logarithm r=radial coordinate of throat profile r'=minimumthroat radius r0=disk radius 50 fy=unit weight of the flowing fluid orthe liquid x=axial coordinate of throat profile xposition of disk inthroat Y0=displacement of float due to head change from ho 55 to hOH Ys=displacement of oat from minimum design head position a=area of theiioat a0=area of the oat chamber 60 zur-depth of the liquid Itwill berecognized by those skilled in the art, from the above teachings of myinvention, that an alternative form may be provided wherein the floathas vertical surfaces and the oat'chamber'has'side walls which curveinwardly. Thus the amount that the liquid will -rise on the side of thefloat varies non-linearly with the force on the valve. The side walls ofthe chamber will follow the same shape relationships as disclosed forthe shaped oat.

Thus it will be seen that I have provided an improved non-linearresistance for the flow control valve which is developed in accordancewith the laws given. The valve in combination with the oat is capable ofrapid response u1 in. s a z 30' 0 l5. 49 O 0.05 16. 90 0.269 D. 10 17.Q2 0. 665 0.15 18. 64 l. 257 0. 20 19. ll 2.184 o. 25 19. 44 3. en

6, and provides an accurate reliable ow control avoiding disadvantagespresent in flow control valves heretofore used.

I have, in the drawings and specification, presented a detail disclosureof the preferred embodiments of my invention, but it is to be understoodthat I do not intend to limit the invention to the specific formdisclosed but intend to cover all modifications, changes and alternativeconstructions and methods falling within the scope of the principlestaught by my invention.

l' claim as my invention:

1. A uid flow control device comprising a valve housing having an inletand an outlet, an orifice defining member forming a throat between saidinlet and outlet Y defining a tiow path therebetween, a poppet diskmember Within said orifice member with one of said members movablerelative to the other to vary the cross-sectional iiow area through theoritice,'one of said members, having a shaped surface contoured to varythe flow area'4 when said movable member is displaced and anon-linearcsupport for themovable means including a oat attached` wherein F is thepressure force on the disk.. F0 is the minimum design Aforce on the diskv e is the base of natural logarithms s is the displacement'of floatfrom minimum vdesign head' position l ln is the natural logarithm H isthe ratio of maximum uid head to minimum duid head ho is the minimumdesign head loss across disk, and Y0 is the displacement of iioat due tohead change from 0 tO hOH. Y* L 2. A fluid flow control devicecomprising a valve hous-v ing having an inlet and an outlet, an orificedefining member forming a throat between said inlet and outlet deiininga flow path therebetween, a poppet disk member within said orificemember with one of said members movable relative to the other to varythe cross-sectional iiow area through the orifice, one of said membershaving a shaped surface contoured to vary the ilovvarea when saidmovable member is displaced, and a non-w linear support for the movablemeans including a float attached to the movable member and supported inabody of liquid and a oat chamber for containing said liquid, thenon-linear support having characteristics in accordance with the laws ais the area of the iioat an is the area of the oat chamber s is thedisplacement of oat from minimum design head positionl .t

ln is the natural logarithm U ,i

H is the ratio of maximum Huid head to minimum uid head hn is theminimum design head loss across disk Y0 is the displacement of oat dueto head change from ho to ,10H

y is the unit weight of the liquid F0 is the minimum design force ondisk E.' is the depth of liquid 3. yA 'fluid ow control devicecomprising a valve housing `having .an inlet and an outlet, orilicedening means in said housing forming a throat between the nletandoutletproviding aflow path therebetween, valve poppetldisk means fwithinthe orifice with one of said means movable relative to `the Aother to'vary the crosssection flow `area with changes in pressure head at thisinlet, one of said means having a face profile contoured to vary theVflow area between saidsm'eans when the movable means is moved, and anou-linear support for the movable means including a float supported ina liquid chamber with the lioat shaped to provide a non-linearresistance for the movable valve member, said face prole of the valvemember contoured to support the movable member in` accordance .with therelationship of anni CdA-#Gianna 2" wherein Cd is the dischargecoeicient A is the area of the opening between the disk and the orificesides eis the base of natural logarithms x' is the position of disk inthroat ln is the natural logarithm H is the ratio of maximum uid head tominimum uid head Y0 is the displacement of oat due to head change 'froming having an inlet and an outlet, orifice defining means in saidhousing between the inlet and outlet providing a throat for a iiow paththerebetween, Valve puppet` disk means within the orifice with one ofsaid means movable relative to the other to vary the cross-section tiowarea with changes in pressure head at this inlet, one of said rmeanshaving a face 'profile contoured to vary the tiow area between saidmeans when the movable means is moved, and a non-linear support for themovable means including a float supported in a uid chamber with thefloat shaped to provide a nonlinear resistance for the movable valvemember, said face proile of the valve `member contoured in accordancewith the relationship of x is the axial coordinate of throat profile 5.A uid ow control device comprising avaivc-uuw ing having an inlet and anoutlet, an orifice defining ,Y

means within said housing providing throat for a flow path therethrough,a poppet disk means within said orifice and movable relative thereto tovaryrthe cross-sectional a float connected to the puppet to provide anonlinear resistance to movement of the poppet disk with variations influid head, and a supporting chamber for said oat containing a liquid,said float having a liquid engaging surface developed in accordance withthe relation- ,l

whereby a nonlinear resistance is provided to control movement of thepuppet disk and a uniform ow is obtained through Athe flow controldevice with variations in head wherein Y r' is the minimum throat radiusY0 is the displacement of tioat due to head change from ho is theminimum design head loss across disk 1n is the natural logarithm H isthe ratio of maximum Huid head to minimum lluid head ro is the diskradius r' is the minimum throat radius t is r-ro, and

Y0 is the displacement of float due to head change from ho to hoH.

t is r--ro a is the area of the float a0 is the area of the tioatchamber F0 is the minimum design force on disk 'y is the unitl weight ofthe liquid e is the base of natural logarithms s is the displacement ofoat from minimum design head position.

References Cited in the tile of this patent UNITED STATES PATENTS1,904,337 Turner Apr. 18, 1933 1,921,145 Albright Aug. 8, 1933 2,619,114Conkling Nov. 25, 1952 2,646,060 .Pensar July 21, 1953 FOREIGN PATENTS411,366 France -......n of 1910 74,254 Austria Mar. 26, 191B'

